feat: a skill creating skill as default

assets/dev-brain/skills/create-dev-brain-skill.md

@@ -0,0 +1,58 @@
+---
+dev_brain: true
+type: skill
+built_in: true
+name: create-dev-brain-skill
+description: Create or update a source-backed skill in Dev Brain. Use when adding reusable instructions that should activate on demand in future development tasks.
+project: DS4Server built-in
+status: verified
+verified_at: 2026-07-30T00:00:00Z
+sources: []
+---
+
+# Create a Dev Brain skill
+
+Create a skill when a repeatable development task needs instructions beyond the model's general knowledge. Keep it concise and source-backed.
+
+## File structure
+
+A Dev Brain skill is one Markdown file, not a directory:
+
+```text
+skills/
+└── skill-name.md
+```
+
+Use this structure:
+
+```yaml
+---
+dev_brain: true
+type: skill
+name: skill-name
+description: State what the skill does and when to use it.
+project: Exact registered project name
+status: needs-review # change to verified only after checking every claim
+verified_at: 2026-07-30T12:00:00Z
+sources:
+  - project: Exact registered project name
+    path: path/to/authoritative-source.md
+    revision: latest-commit-that-changed-this-file
+---
+
+# Human-readable skill title
+
+Write direct instructions for completing the task. Link to related Dev Brain pages when useful.
+```
+
+Use lowercase letters, digits, and hyphens for `name`. Put all trigger conditions in `description`. Cite at least one registered project source, using the exact per-file revision for a clean Git file or its lowercase SHA-256 hash when required by `schema.md`.
+
+## Create and activate
+
+1. Call `dev_brain_info` and read `purpose.md` and `schema.md`.
+2. Read the authoritative project sources for the instructions.
+3. Write `skills/<name>.md` with current evidence and `status: verified`; use `needs-review` until every claim is checked.
+4. Append the material change to `log.md`.
+5. Run `dev_brain_validate`.
+
+Validation is the activation step. It verifies the file, rebuilds generated `skills.md`, and makes the skill's name, description, and path available to the agent. Never edit `skills.md` directly.